Page 32 - Ranger SPM 2022 Chemistry

Chemistry SPM Chapter 2 Carbon Compound

Homologous series
Ester
Number Number of
of carbon carbon atoms General formula is
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atoms per per molecule C H 2m+1 COOC H 2n+1 ,
m
n
molecule (m) (n) m = 0, 1, 2…
n = 1, 2, 3…
Name Molecular formula
0 1 Methyl methanoate HCOOCH
3
1 2 Ethyl ethanoate CH COOC H 5
3
2
2 3 Propyl propanoate C H COOC H
2 5 3 7
3 4 Butyl butanoate C H COOC H
3 7 4 9
4 5 Pentyl pentanoate C H COOC H
4 9 5 11
Physical properties of ester Solution
1. Exists as a colourless liquid at room IUPAC
temperature with a sweet fruity Structural formula nomenclature
smell
H H H H
2. Has a pH value of 7 & & & &
H!C!C!C!C!OH Butan-1-ol
3. Less dense than water & & & &
H H H H
4. Insoluble in water but soluble in
organic solvents H H H O
& & & ' Butanoic
5. Easily vaporises at room temperature H!C!C!C!C!OH
& & & acid
H H H
Example 2
H O H
Complete the following table by filling in the & ' & Methyl Form 5
structural formulae of: H!C!C!O!C!H ethanoate

&
&
(a) Butan-1-ol H H
(b) Butanoic acid
(c) Methyl ethanoate H H O H H H
(d) Propyl propanoate & & ' & & & Propyl
(e) Propyl ethanoate H!C!C!C!O!C!C!C!H propanoate
& & & & &
H H H H H
H H H O H
& & & ' & Propyl
H!C!C!C!O!C!C!H
& & & ethanoate
H H H

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